Pulverizers are used by farmers during planting season to help prepare an ideal seedbed. Since yield is a direct result of germination, which is dependent on soil conditions at planting time, having an ideal seedbed is desired. Pulverizers break up clods and insure good seed to soil contact, reducing germination time. Since the seedbed is firmed and air pockets are eliminated, capillary action in the soil is also increased making more moisture available to the plant through its root.
As fields become larger and individual farms cover more acres, equipment has become larger to cover more land in less time. One way to cover more land is to make machinery wider, but with that comes the problem of transporting it from field to field. Wide machinery is typically folded allowing for transport on public roadways. Inherent to a folding piece of machinery is to have a hinge point, making the wing fairly rigid with the center section in that it cannot follow the contour of the field as drawbar heights vary.
FIG. 1, for example, shows a conventionally hinged pulverizer 10 having a drawbar 11 for attaching at one end 12 to a tractor (not shown) for towing the pulverizer. Drawbar 11 is attached at its other end to pulverizer center section 13. Center section 13 includes ground engaging roller wheels 14 constituting the center roller, transport wheels/rockshaft assembly 15, and hinge points 16, 17. Wing roller assemblies 18 with ground engaging roller wheels 19 extend transversely on opposite sides of center section 13 and are fairly rigidly connected to center section 13 at the hinge points 16, 17 respectively. When the pulverizer 10 is to be transported, wing assemblies 18 are folded about hinge points 16, 17 to a position shown, for example, in FIG. 2. A double acting hydraulic cylinder (not shown) on the center section acts to initiate and carry out the folding. Wing hinges 24 at hinge points 16, 17 connect the wing assemblies 18 to center section 13 of the pulverizer by conventional means of a hinge pin 20 and center section hinge plates and barrel 21, shown in FIG. 6 just prior to connection.
As described above, the pulverizer, parts and hinge connections for the wings are all well known in the prior art. However, a difficulty with this design is that when the pulverizer is operational and towed over fields that are not perfectly level, the height of drawbar 11 varies and weight distribution on the ground engaging components is affected. In fact, both the said weight distribution and the depth control of the ground engaging components are both affected by varying drawbar heights (due to ground contours), ground contours at the rollers, and ground obstructions (stones) on the winged pulverizer. It is common in pulverizers for the wing rollers 19 to be set back from the center rollers 14 to provide some overlap, ensuring that over the total width of the pulverizer there are no strips of unconditioned soil. The varying drawbar heights come into consideration because the wing rollers are not in line with the center section rollers. More specifically, FIGS. 3-5 illustrate the effects of this design. In FIG. 3, the conventionally hinged pulverizer (shown from the left side) is being towed toward the left down from the top of a ground contour 25. Shown in exaggerated form, the weight of the center section is transferred to the wing rollers 19 and the center section rollers 14 tend to be lifted off the ground. In FIG. 4, a view towards the rear of the conventionally hinged machine of FIG. 3, the weight of the center section transferred to the wings causes them to lift at their outer extremities. Since the wings are allowed to flex about the hinge points, the wing rollers closest to the hinge now have to carry both the weight of the center section and the weight of the wings lifted off the ground, resulting in a poorly conditioned seed bed. As again viewed from the left side of the pulverizer, FIG. 5 shows what typically happens from the scenario of FIGS. 3 and 4. The center section is heavier than the wings due to the weight of the transport wheels/rockshaft assembly and the drawbar causing a reaction resulting in the wings picking up at the extremity to a point where the weight carried by the center section is balanced by the weight carried on the wings. Ground contact is limited on the wing rollers 19, the center section conditioning is limited due to the reduced weight on the center section rollers 14, and the wing roller portions nearest the hinge are forced to carry extra weight that may cause a packed groove in the soil.
In short, with the current conventionally hinged design, weight from the wings is transferred to the center section or vice versa. When this happens, portions of the wings or center section are not engaging the soil, making for inconsistent conditioning. Also, since weight transfer takes place, the rollers in contact with the soil have to carry extra weight, which gives the possibility of those rollers sinking into the ground and pushing the soil rather than rolling over the top of the soil, or packing the soil making it more difficult for germinating seeds and plants to break through. The conventional hinge design of FIG. 6 allows the wings to fold over the top of the center section, but does not allow any freedom for the wings to maintain uniform ground control as the drawbar height changes, causing the machine to rock about the center section rollers.
Attempts have been made in the past to deal with farm machines operating on uneven ground. See, for example, U.S. Pat. No. 93,959 (1869) involving the connection of two harrows operating side by side to form a double harrow. The side of a first harrow adjacent its longitudinal ends has two hoops, and the side of a second harrow adjacent its longitudinal ends has two arms to fit within the corresponding two hoops in the first harrow when the second harrow is positioned at a right angle to the first harrow. There is no center section between the two harrows which are positioned side by side, and no folding rotation between the two harrows. Each frame can move up and down or back and forth with respect to the other to a limited extent to provide a limited independent movement over uneven ground. There is no hinge or joint connection between the two frames. Each harrow frame has a separate chain draught connection for the protection and comfort of the towing horses. Among other deficiencies, the design of the '959 patent does not lend itself to solving the above-described difficulties of the conventionally hinged pulverizer having a drawbar, a center section with rollers, and the center section rollers positioned forward of folding-wing rollers.
Further, see for example U.S. Pat. No. 6,325,155 (2001) involving a design having a center frame and opposing double wings of inner and outer wing sections which are intended to follow ground elevation. A linkage allows the inner wings to move perpendicular to the center section, and there is a draft cable to help distribute the draft load generated by the outer wings. A universal joint having three axes of freedom connects the inner wing sections to the center section. A differential control rod parallel to the center section is required and which controls the universal-joint. An “L”-shaped linkage controls the movement of a pivot in a slot, the linkage being pivotally attached to the center frame and differential control bar. The center frame and universal joint are rotated ninety degrees in passing between the transport and field operational modes. The wings fold rearwardly into the transport mode. Altogether, this three-axis arrangement of parts and motions is overly complex for the needs satisfied by applicant's invention involving a considerably simpler structure and functioning.